1. Field of the Invention
The present invention relates to video surveillance systems in general, and to an apparatus and method for the semi-automatic examination of the history of a suspicious object, in particular.
2. Discussion of the Related Art
Video surveillance is commonly recognized as a critical security tool. Human operators provide the key for detecting security breaches by watching surveillance screens and facilitating immediate response. For many transportation sites like airports, subways and highways, as well as for other facilities like large corporate buildings, financial institutes, correctional facilities and casinos, where security and control plays a major role, video surveillance systems implemented by Close Circuit TV (CCTV) and Internet Protocol (IP) cameras are a major and critical tool. A typical site can have one or more and in some cases tens, hundreds and even thousands of cameras spread around, connected to the control room for monitoring and at times also for recording. The number of monitors in the control room is usually much smaller than the number of cameras on site, while the number of human eyes watching such monitors is smaller yet.
The human operator's tiring and boring job of watching multiple cameras on split screens, when most of the time nothing happens is facilitated by existing techniques. These techniques include the identification and tracking of distinguishable objects in each of the captured video streams, and marking these objects on the displayed video streams. Objects are identified and tracked at their first appearance in the video stream. For example, when a person carrying a bag walks into a monitored area, an object is created for the person and the bag together. Alternatively an object is identified as such once it is separated from a previously identified object, for example a person walking out of a car, a left luggage and the like. In the former example as soon as the person leaves the car, he is identified as a separate object than the car, which in itself can be defined as an object.
More advanced systems such as NICEVision Content Analysis applications manufactured by NICE Systems, Ltd. Of Ra'anana Israel can further alert the user that a situation which is defined as attention-requiring is taking place. Such situations include intrusion detection, a bag left unattended, a vehicle parked in a restricted area and others. In addition to the generated alert, the system can assist the user in rapidly locating the situation by displaying on the monitor one of the available video streams showing the site of the attention-requiring situation, and emphasize, for example by encircling the problematic object by a colored ellipse.
Alerts are triggered by a variety of circumstances, one or more independent events, or combination of events. For example, alert can be triggered by: a specific event, predetermine time that elapsed from a specific event, an object that passed a predetermined distance, an object that entered to or existed form a predetermined location, predetermined temperature measured, weapon noticed or otherwise sensed, and the like.
In order to avoid alerts overload, the system often generates an alert not immediately following the occurrence of an alert-requiring situation, but only after a predetermined period of time has elapsed and the situation has not been resolved. For example, an unattended luggage might be declared as such if it is left unattended for at least 30 seconds. Therefore, once the operator becomes aware of the attention-requiring situation, some highly valuable time was lost. The person who abandoned the bag or parked the car in a parking-restricted zone might be out of the area captured by the relevant camera by the time the operator has discovered the abandoned bag, or the like. The operator can of course playback the relevant stream, but this will consume more, and potentially a lot more valuable time and will not assist in finding the current location and route followed by of the required object, such as the person who abandoned the bag, prior to and following the abandonment.
An investigation is not necessarily held in response to an alert situation as recognized by the system. An operator of a monitored site can initiate an investigation in response to a situation that was not recognized by the system as alert triggering, or even without any special situation at all, for example for training purposes.
There is therefore a need in the art for a system that will assist the operator in examining the history of situations, and attaining history and current information about objects that might have been involved with the situation.